diff --git a/src/lock_tree/locktree.c b/src/lock_tree/locktree.c
index 843934143a7..902fe741e0a 100644
--- a/src/lock_tree/locktree.c
+++ b/src/lock_tree/locktree.c
@@ -933,7 +933,19 @@ int toku_lt_acquire_range_write_lock(toku_lock_tree* tree, DB_TXN* txn,
         __toku_lt_is_infinite(key_left))                    return EINVAL;
     if (tree->duplicates  && key_right != data_right &&
         __toku_lt_is_infinite(key_right))                   return EINVAL;
-    assert(FALSE);
+
+    toku_point left;
+    toku_point right;
+    
+    __toku_init_point(&left,   tree,  key_left,  data_left);
+    __toku_init_point(&right,  tree,  key_right, data_right);
+
+    /* Verify left <= right. */
+    if ((key_left != key_right || data_left != data_right) &&
+        __toku_lt_point_cmp(&left, &right) > 0)             return EDOM;
+
+
+    return ENOSYS;
     //We are not ready for this.
     //Not needed for Feb 1 release.
 }
diff --git a/src/lock_tree/locktree.h b/src/lock_tree/locktree.h
index 35d2df3d8bb..7c11554d45a 100644
--- a/src/lock_tree/locktree.h
+++ b/src/lock_tree/locktree.h
@@ -251,6 +251,8 @@ int toku_lt_acquire_write_lock(toku_lock_tree* tree, DB_TXN* txn,
  *                            If (key_left, data_left) >  (key_right, data_right) or
  *                          In a nodup db:      if (key_left) >  (key_right)
  *                          (According to the db's comparison functions.
+ *      ENOSYS:             THis is not yet implemented.  Till it is, it will return ENOSYS,
+ *                            if other errors do not occur first.
  * Asserts:
  *      The EINVAL and ERANGE cases described will use assert to abort instead of returning errors.
  *      If this library is ever exported to users, we will use error datas instead.